纳米C—S—H/PCE对硅酸盐-硫铝酸盐复合水泥凝结硬化的影响

研究了纳米C—S—H/PCE对硅酸盐-硫铝酸盐复合水泥凝结时间、早期水化历程及抗压强度的影响,采用XRD、TG、pH计和SEM等分析测试手段对早龄期水化产物和液相碱度等进行表征,探讨了纳米C—S—H/PCE对硅酸盐-硫铝酸盐复合水泥的增强机理。结果表明：掺加纳米C—S—H/PCE能有效缩短硅酸盐-硫铝酸盐复合水泥浆体初凝及终凝时间,当C—S—H掺量≥1.0%时,硅酸盐-硫铝酸盐复合水泥的初、终凝时间差明显缩短。纳米C—S—H/PCE加快了硅酸盐-硫铝酸盐复合水泥水化放热速率,提高了总的水化放热量,早期水化产物生成数量多,但对水泥水化产物类型没有影响,硅酸盐-硫铝酸盐复合水泥体系8、12、16 h的抗压强度显著提高。     

掺合料对过硫磷石膏矿渣水泥早期性能的影响

研究了矿物掺合料偏高岭土、硅灰、硫铝酸盐水泥和外加剂水玻璃对过硫磷石膏矿渣水泥凝结速率、早期强度等早期性能的影响规律,并通过XRD、SEM等对过硫磷石膏矿渣水泥的水化及结构发展进行了研究。结果表明,在过硫磷石膏矿渣水泥中掺加水玻璃和偏高岭土,能显著提高该水泥的凝结速率和早期强度,3d、7d、28d抗压强度分别达到17MPa、32MPa、46MPa。     

水泥改良冻土过程水分转化规律及对强度的影响

为保证多年冻土区地基的稳定性及解决多年冻土区土方材料短缺的问题,分别使用硫铝酸盐水泥(SAC)和普通硅酸盐水泥(OPC)对冻土进行改良。通过无侧限抗压强度试验得到两种水泥在不同掺量及不同养护龄期下的强度特征,同时,使用离心机法及冻干法对水泥改良冻土过程中的自由水、矿物水及结合水的变化进行测定,揭示水泥改良冻土过程中的水分转化规律,并建立矿物水、结合水量与水泥改良冻土强度的内在联系。结果表明:硫铝酸盐水泥改良冻土的强度明显高于普通硅酸盐水泥,并且具有显著的早强特性。硫铝酸盐水泥改良冻土在养护初期水分转化速率较普通硅酸盐水泥快,但矿物水及结合水的转化量少。硫铝酸盐水泥改良冻土中的矿物水和结合水对强度的贡献更为突出。硫铝酸盐水泥更适合用于冻土的改良。     

石灰石粉铝酸盐水泥复合体系的水化反应

石灰石粉具有水化活性,能与硅酸盐水泥中的C₃A、铝酸盐水泥中的CA、CA₂等铝酸盐矿物发生反应,水化产物为水化碳铝酸钙。利用微量热仪法、胶砂强度和X射线衍射（XRD）,研究不同比例的石灰石粉铝酸盐水泥复合体系的水化反应,结果表明：石灰石粉会加快铝酸盐水泥的水化进程,水化过程诱导期缩短,放热速率峰值下降;复合体系中石灰石粉占比越高,早期水化反应速率越快,但水化反应放热量越低;相对而言,复合体系中石灰石粉掺量为20%时石灰石粉参与反应程度最高,且掺量为20%时石灰石粉对复合体系强度有显著贡献。随复合体系中石灰石粉比例增加,铝酸盐水泥水化产物越来越不明显;石灰石粉掺量为20%~40%时,水化碳铝酸钙XRD特征峰相对最明显,复合体系中石灰石粉与铝酸盐水泥存在一个最佳的比例范围。研究表明,石灰石粉与铝酸盐水泥间会发生明显的水化反应,石灰石粉与铝酸盐水泥复合有望制得一种新型胶凝材料。     

水泥基复合胶凝材料改性聚合物修补砂浆的试验研究

针对硫铝酸盐水泥基修补材料凝结时间快、抗折强度倒缩等问题,提出以普通硅酸盐（PO）- 硫铝酸盐水泥（SAC）复合改性聚合物快速修补材料性能,探究 PO-SAC 复合胶凝体系对聚合物修补砂浆的新拌性能和力学性能的影响,并且进一步研究了复合体系对砂浆界面粘结性能的影响,采用 SEM 分析解释宏观性能变化。结果表明：当 PO 占复合胶凝体系比例达 90% 时,聚合物修补砂浆的凝结时间相比 SAC 明显延长,满足修补需求;流动性能良好,砂浆呈现微膨胀性,28 d 时的收缩率为 -3.21×10-4;早期强度高,1 d 抗压强度达到 26.1 MPa,且后期抗压、抗折强度增长幅度大;界面粘结性能优异,28 d 粘结强度可达到 4.4 MPa。随着PO 的掺入,复合胶凝体系的水化产物钙矾石（AFt）会逐渐减少,砂浆微观形貌不致密,不利于水泥浆体早期强度和收缩的发展。     

利用污水厂污泥配料煅烧水泥熟料研究

通过生料易烧性试验、水泥熟料矿物岩相分析、XRD、SEM、水泥胶砂强度试验等，对利用污水厂污泥代替部分粘土配料煅烧硅酸盐水泥熟料的过程，并对制备熟料的微观特征进行了研究。结果表明：污水厂污泥代替部分粘土烧制的水泥熟料，其矿物结构与常规的硅酸盐水泥熟料完全相同，且由污泥配料煅烧的熟料烧成温度有降低的趋势；其水泥水化和凝结、硬化过程与常规硅酸盐水泥完全相同；其水化产物结构与常规硅酸盐水泥完全相同；水泥胶砂强度达到50．0MPa。     

Zn~(2+)对硫铝酸盐和硅酸盐水泥水化性能的影响

研究了Zn2+对硫铝酸盐及普通硅酸盐水泥的水化和物理力学性能的影响,采用XRD和SEM分析2种含Zn2+水泥水化产物相组成、形貌,采用ICP-AES测定水化产物浸出液中Zn2+的浓度。结果表明:Zn2+可促进硫铝酸盐水泥的早期水化,阻碍普通硅酸盐水泥的水化;掺入Zn2+后,两者的强度都降低,但是降幅有所差别;Zn掺量为1%时,2种水泥水化产物中Zn的浸出浓度均低于国家浸出毒性标准,但是硫铝酸水泥对Zn2+的固化率约为普通硅酸盐水泥的4倍。     

聚合铝改性磷石膏基超硫矿渣胶凝材料制备与性能研究

以硫酸盐为主要激发剂,辅以少量硅酸盐水泥激发矿渣,破坏矿渣玻璃体的空间结构,促进矿渣水化,研制出一种低污染环境友好型胶凝材料——磷石膏基超硫水泥。使用新型活性聚合铝为添加剂解决超硫水泥早期强度较低、凝结时间长的问题。对活性聚合铝改性超硫水泥的凝结时间、长期力学性能作了研究;使用水化热、XRD、SEM等测试技术分析其改性提升机理。研究结果表明:掺入活性聚合铝可显著加快超硫水泥早期水化速率,促进胶凝材料水化,提高硬化胶凝材料密实度。     

高温煅烧石膏对C3S和C2S水化过程的影响

利用XRD、TMS-GLC（三甲基硅烷化）等方法,对C3S-CaSo4.2H2O-H2O、C3S-CaSO4-H2O、C2S-CaSo4.2H2O-H2O、C2S-CaSo4-H2O四个系统的水化过程进行了研究,测定了结合水生成量、Ca(OH)2生成量、[SiO4]四面体聚合度及浆体的强度。结果表明：适量的煅烧石膏或二水石膏均能促进C3S和C2S的水化,但两类石膏的促进效果相近;指出了同二水石膏相比,煅烧石膏提高硅酸盐水泥强度机理的研究,应从它对水泥中铝酸盐矿物的水化和浆体结构形成过程的影响方法进行。     

石膏的形态对C2S浆体强度的影响

研究了二水石膏、600℃、800℃、1000℃煅烧石膏对C2S浆体强度的影响，结果表明：石膏的掺入，能提高C2S浆体的强度；煅烧石膏比二水石膏更能提高C2S浆体的强度。证明了石膏不仅对硅酸盐水泥中C3A的水化产生影响，同时亦对硅酸盐矿物的水化有促进作用。     

Carbonation of sulphoaluminate cement with layered double hydroxides

The increasing importance of the ecologically minded production of building materials makes it necessary to develop reasonable alternatives to the CO2-intense production of ordinary Portland cement （OPC）. The development of new or modified concrete is an important part of existing strategies to improve performance and minimize life-cycle costs. Therefore, we investigated carbonation resistance properties of sulphoaluminate cement （SAC） concrete incorporating layered double hydroxides （LDHs）. X-ray diffraction （XRD） and IR-spectroscopy were employed to characterize the component and structural changes of LDHs and cement paste before and after carbonation test. Carbonation resistance of concrete was experimentally evaluated. Finally, carbonation of Portland cement and SAC concrete was compared. The experimental results show that carbonation depth decreases remarkably with the addition of LDHs, especially the calcinated LDHs. Carbonation depth of SAC concrete is smaller than that of PC concrete regardless of curing time.     

低水胶比掺膨胀剂的水泥水化特性

应用XRD、TG-DTA和温度测量等方法，研究了低水胶比条件下普硅水泥和膨胀水泥的水化特点。结果发现，膨胀水泥水化各龄期中AFt的含量和CH的早期含量明显增加，水化后期CH量则与普硅水泥石基本相当。膨胀水泥硬化浆体的后期膨胀主要依靠凝胶状AFt吸水肿胀而形成驱动力。膨胀刑的组分对膨胀水泥的水化热有明显影响，如果膨胀剂含有硫铝酸盐类矿物，则可能造成体系水化热的升高。     

Effect of Fine Steel Slag Powder on the Early Hydration Process of Portland Cement

1 IntroductionSteel slag is the waste residue of fluxing mineralsused in the process of steel producing. Its dischargeamount is about 10 % of the production of steel . Steelslag hasn’t been utilized widely and effectively in a longperiod of time[1]. Hundreds of million tons of steel slagare deposited,andthe amount is still increasing withtensof milliontons every year .The deposited steel slag occu-pies great amounts of farmlands and induces serious en-vironment problems . The main chemical c…     

石灰石硅酸盐水泥的水化反应特性

为生产环境型水泥,用石灰石粉(简称LSP)置换部分水泥熟料的方法进行了实验。结果表明,C3S的初期水化反应率随LSP的置换率和粉末度的增加而增加,但龄期28 d的水化反应率与普通水泥(简称OPC)基本持平;C3A的初期水化反应率明显下降,但龄期3 d以后就显示出与OPC相同的反应率;碳酸钙主要在龄期7 d之内参与反应生成Monocarbonate,且与C3A水化反应有着密切的相关关系,此后几乎不参与反应。     

中间相C3A对硅酸盐水泥水化的影响

在现有理论基础上,探讨了中间相Ｃ３Ａ对硅酸盐水泥水化反应历程的影响,认为Ｃ３Ａ矿物与硅酸盐矿物水化产物ＣＨ反应仅是中间过程,其反应前后未改革浆体中的ＣＨ浓度,提出了Ｃ３Ａ吸收高浓度处的ＣＨ,经反应将其输到ＣＨ浓度较低的Ｃ３Ａ水化产物周界中,通过在原质下的吸收放出的“囊泵”作用促进硅酸盐水泥水化,该作用是非显著的物理作用,而非化学作用。     

Hydration mechanism of sulphoaluminate cement

The feasibility of sulphoaluminate cement (SAC) utilization in support mortar was studied. Setting time and strength of as-received sulphoaluminate cement (SAC) paste were examined, hydration kinetics behavior was determined through Isothermal Calorimeter, and hydration mechanism was investigated by X-Ray diffraction analysis (XRD) and field emission scanning electron microscopy analysis(FSEM). Results showed that as-received SAC contained 61% of anhydrous calcium sulfate (3CA·CaSO4) and dicalcium silicate (C2S). The strength after 1 day or 3 days grew to 68.6% or 85.7% of that after 28 days respectively, while most of hydration heat was released within 1 day. The emergency of three exothermic peaks at acceleration stage was found and hydration kinetics model was established choosing the terminal time of the first exothermic peak at accelerating stage as the beginning of accelerating stage. XRD analysis suggested that large amount of ettringite (AFt) was produced at early age and FSEM observation revealed that ettringite (AFt) formed in sulphoaluminate cement (SAC) paste was characterized of different morphology which was proved to be caused by different ion concentrations.     

Model Analysis of Initial Hydration and Strueture Forming of Portland Cement

The auto efficiently hydration heat arrangement and the non-contacting electrical resistivity device were used to test the thermology effect and the resistivity variation of Portland cement hydration. The structure forming model of Portland cement initial hydration was established through the systematical experiments with different cements,the amount of mixing water and the chemical admixture.The experimental results show that,the structure forming model of cement could be divided into three stages,i e,solution-solution equilibrium period,structure forming period and structure stabilizing period.Along with the increase of mixing water,the time of inflexion appeared is in advance for thermal process of cement hydration and worsened for the structure forming process.Comparison with the control specimen,adding Na_2SO_4 makes the minimum critical point lower,the flattening period shorter and the growing slope after stage one steeper.So the hydration and structure forming process of Portland cement could be described more exactly by applying thc thermal model and the structure-forming model.     

复合浆体中粉煤灰和水泥水化反应程度的测定

采用盐酸选择溶解法测定粉煤灰的水化程度,再结合水化热法计算复合浆体中水泥的水化程度。试样结果表明,在水化早期粉煤灰仅作为惰性材料填充于复合浆体的孔隙中。随着粉煤灰掺量的增大,水泥的水化程度越高,单位体积中水化产物的总体数量仍为减少。     

Model Analysis of Initial Hydration and Structure Forming of Portland Cement

The auto efficiently hydration heat arrangement and the non-contacting electrical resistivity device were used to test the therrnology effect and the resistivity variation of Portland cement hydration. The structure forming model of Portland cement initial hydration was established through the systematical experiments with different cements, the amount of mixing water and the chemical admixture. The experimental results show that, the structure forming model of cement could be divided into three stages, i e, solution-solution equilibrium period, structure forming period and structure stabilizing period. Along with the increase of mixing water, the time of inflexion appeared is in advance for thermal process of cement hydration and worsened for the structure forming process. Comparison with the control specimen, adding Na2SO4 makes the minimum critical point lower, the flattening period shorter and the growing slope after stage one steeper. So the hydration and structure forming process of Portland cement could be described more exactly by applying the thermal model and the structure-forming model.